Stardate Unknown: A damaged ship exits the wormhole near Deep Space Nine and the Federation receives their first visitor from the Gamma Quadrant. Since O'Brien guided the visitor to one of the station's ports safely, Commander Sisko allows the Chief the luxury of first contact with the species. While the humanoid, referring to itself only as Tosk, takes in the sights and sounds of the station, Chief O'Brien, acting as his guide, tells him a bit about life in the Alpha Quadrant as he tries to find out more about the visitor.
When the Cardassian occupation of Bajor ended in 2369, the mining space station Terok Nor was left abandoned, its systems ripped out. By invitation of the Bajoran provisional government, Starfleet stepped in to oversee the rebuilding and day-to-day operations of the newly christened Deep Space Nine.
The years of Starfleet's nonintervention into Cardassian matters, however, had taken its toll on relations with the Bajorans. Consequently, Starfleet's position was a tenuous one; many Bajorans, suspicious and hostile as a result of decades of Cardassian oppression and brutality, did not greet the Federation's presence with open arms. The Federation's assistance is put to the test as DS9 becomes a center of travel and commerce that stretches into the Gamma Quadrant.